Dr. Sierra was born and raised in the small San Joaquin Valley town of Madera, CA.
After earning his undergraduate degree in Biological Sciences at UC Davis, he stayed in Davis for Veterinary School, graduating in 2004. He then completed a one-year internship in small animal medicine and surgery at Veterinary Medical and Surgical Group in Ventura. He joined Pets Unlimited as an associate veterinarian in May 2007. Dr. Sierra has particular interests in cardiology, radiology (including ultrasonography), emergency medicine and endocrinology. He was hired as the new Pacific Heights Hospital Medical Director in 2019.
He currently resides in San Francisco with his wife, Dr. Kristen Haviland (also a veterinarian!), and their menagerie (two sons, two dogs, two cats and a few fish).